Riveter



March l, 1932. R. s. osBoRNE RIVETER Filed Jan. 1e. 1930 Patented Mar.l, 1932 PATENT OFFICE RAYMOND S. OSBORNE, F SEWICKLEY, PENNSYLVANIARIVETER Application led January 16, 1930. Serial No. 421280.

This invention relates to improvements in compression riveters which actby direct pressure, and is particularly directed to apparatus forcontrolling the pressure developed within the riveter and against thework and for returning the rivet driving` mechanism after a drivingmovement.

As disclosed in the Osborne Patent No. 1,660,720, a mechanism isprovided for automatically controlling the riveter for relieving thepressure to the rivet driving cylinder at a 'predetermined degree asdetermined by the size of the rivet and the type of the work.

This control was designed to eliminate damage to the work and rivets bexcess pressures, having particular application to riveters used infield work and general plate or structural shops where a uniform linepressure must be maintained for operating various pneumatic devices.

Each riveter is operated under independent pressure control by means ofthe patented automatic control set forth above. The driving cycle isinitiated by a hand lever in direct mechanical connection with the mainvalve of the riveter, and the lever automaticallyr returned when apredetermined pressure has developed in the rivet driving cylindersuflicient to pass into a control cylinder which returns the releasedcontrol lever.

It is an object of this invention to provide an improved control forautomatically relieving the pressure applied to the rivet by the powerpiston at an arbitrarily set pressure and to additionally permit the useof a hand control means entirely manually operated independently of theautomatic pressure relieving control, whereby any desired degree ofpressure or all the line pressure may be applied for reversing the mainvalve of the riveter if the automatic system is not needed. The controlsystem and devices for automatically stopping and returning or entirelymanually controlling the rivet driving piston have been shown appliedfor operating the usual main valve of a standard commercial rivet of thetoggle type, the entirely manual control referred to being aconventional part of this standard riveter with the improvement in thisinstance residing in the line pressure.

cooperating systemfor selective manual or automatic control.

Another object is to provide a trigger valve which is manually moved forinitiating the power stroke of the piston and which is automaticallyactuated by a control valve for automatically stopping the power strokeat a predetermined pressure.

Another object is to provide that the trigger valve may be disposed atany convenient 00 position in the air conduits to the riveter, dependingon the position of the operator for advantageous operation of theriveter.

It is a further object of this invention to lprovide a piston strokecontrolling means which after a predetermined degree of pressure hasbeen developed behind the piston in its driving stroke and upon thedesired pressure being applied, automatically relieves the pressure andreturns the piston under full This arrangement is exceedingly ellicientbecause of the simplicity and rapidity with which the driving piston isreturned, the speed of return always being uniform and independent ofthe particular driving pressure exerted. It is advantageous to use ahigh pressure air supply greater than that needed to drive the rivetssince the speed of the main or power piston is much higher than if onlythe. amount of pressure needed to drive the rivet is in the supply. Itwill readily be seen that utilizing high pressure to fill the drivingcylinder and cutting off the pressure when suiicient is much faster thanto supply the total pressure needed and 85 wait for the cylinder to tillup completely with this pressure of air. In other words, assuming thatrivets are being driven under low pressurethe high pressure from thelield line has greater velocity in entering the driving cylinder and thepiston consequently moves more rapidly to that low pressure at which thedrive is relieved,

It will readily be apparent in the application to the standard toggletype riveter that 05 the piston against which the air is admitteddirectly from the trigger valve of the control may either be theindependent piston connected to the lever operating the standard controlslide valve of the power piston as illustrated, or the slide valve maybe in tho form of a piston directly actuated by air from the triggervalve. Each arrangement is distinctly advantageous.

Further objects and advantages will be v more fully set forth in thedescription of the toggle joint type for operating the usual powerpiston control valve, certain portions of the improved control mechanismand riveter being shown in section to fully illustrate the mechanism andthe air circuit.

Figure 2 is a sectional view taken longitudinally of the trigger valvewhich controls the degree of pressure applied to the rivets.

The improvement is illustrated in conjunction with a commercial toggletype riveter, driving the rivets under direct pressure. The issuedpatent, mentioned above, discloses a control piston directly connectedto the lever actuating the main valve on the toggle actuating air motor,the air to the control piston being supplied from the power or drivingside of the motor through an unloader or control valve. The unloader orcontrol valve is adjustable to permit the passage of air at a desireddegree of ressure, thus actuating the control piston an returning thecontrol leve'r to normal position, whereupon the main valve of the motoris reversed and the motor piston returned under full line pressure.

The rivet setting stroke in the present construction is manually startedeither through a hand lever, which is disposed relative to the dies ofthe riveter, or through an automatically reversed trigger valve whichmay be laced at any convenient point. Through independent use of thehand lever it is possible to operate the riveter to use any o r fullline pressure independent of the automatic mechanism which must actthrough the trigger valve. The power piston is returned in the instanceof inde endent use of the hand lever by manually shi ting or releasing aspring returned hand lever. When the throttle valve is used, theoperator need pay no more attention to that operation after releasingthe throttle since 1t is automatically reversed and the power pistonthereafter returned.

Therefore, the vfollowing description sets forth two methods of controlwhereby the riveter can be operated entirely manually through the usualcontrol lever at the dies, or through a trigger valve either at thepoint of the dies or at any remote position, the trigger valve beingmanually tripped to initiate the driving stroke and automaticallyreversed for returning the mechanism to normal position.

Referring to the figures of the drawings, the yoke frame 5 of theriveter provides a throat into which the plates, or Work to he rlveted,are inserted. The lower die 6 is immovably fixed to one side of the yokeand the lupper die 7 is attached to a plunger 8. The

The cylinder l5 of the air motor has aI main control valve 16 mountedthereon, to which valve the main air supply line 17 is connected. Threepassageways 18, 19, 20, extend from the casing of the valve, 18 thereofextending to the back of the cylinder, being the feed conduit for therivet driving stroke, 19 extending to the front end of the cylinder forretirning the piston, and 20 extending to the atmosphere as an exhaustpassageway.

The valve 16 within the casing provides a recess 21 alternatelyconnecting the forward and reverse passageways 18, 19 with the exhaustpassageway 20, and alternately opening one of the passageways 18, 19 tothe main air supply 17 through the interior of the valve casing. Thevalve 16 is actuated by means of an arm 22 connected to theV outersquaredend of a rock shaft 23 carrying a slide valve actuating linger24:. The arm 22 is connected to the swinging end of a fulcrumed handlever 21 pivoted to the lower aw of the frame, the connection being bymeans of a link 21a pivotally connected at fits respective ends to thearm 22 and to the control lever 21. l

The foregoing description sets forth the arrangement of the parts in thecommercial type riveter, providing a simple manual control in the formof a hand lever for starting the ,rivet driving stroke and reversin thesame when the operator has determine that a sufcient pressure has beenap lied to the rivet. It usually occurs through t is arrange'- ment,that the full line pressure is applied to the rivet, the application ofpartial line pressure requiring careful timing since the riveter actsextremely rapidly.

The control circuit of the present invention comprises, in general, ana1r conduit 25 extending from the rear of the air motor to an unloaderor control valve 26, then from the control valve 26'to a trigger valve27, the trigger valve controlling the flow of air from a branch 28 ofthe main air line to a conduit 29 extending to the control piston 30.The trigger valve 27 is operative, when actuated manually, to connectthe main air passageway with the control piston 30 as above described,and is automatically reversed by air under pressure coming through thecontrol valve thereby exhausting the air in back of the control pistonto permit a spring 31 to return the control lever to normal startingposition and cause the reverse movement of the air motor piston. Thecontrol `piistonis disposed a plunger 46. The plunger is actuated by ina cylinder attached to t e riveter frame, means of a trigger 4 pivotallymounted on and the piston rod thereof is connected to the manuallyoperated control linkage.

Describing the various elements of the control circuit in detail, a stopvalve 32, a choke valve 33, and an air pressure gauge 34 are inserted inthe conduit extending from the forward end of the cylinder of the airmotor. The choke valve is inserted in the line for the purpose ofdelicately controlling the flow of air to the unloader valve, it havingbeen found that as the main valve of the air motor is opened, a suddenrush of air to the back of the large piston causes a sudden low of airthrough the control line and the control valve is unseated prematurelyor improperly. Adjustment of the choke valve eliminates this prematureaction.

Through the use of the gauge, the exact pressure at which the controlvalve acts may be determined, and by adjustment of the valve, an exactdegree of pressure may be exerted on the rivet in a given operation. Bymeans of a scale and pointer on the control valve, the scale determinedby pressure readings at various settings of the pointer, the

gauge can be dispensed with after the scale is determined.

The control valve comprises a body or casing 35 and a spring-pressedplunger 36 having a ball 37 at its forward end seated against the intakeopening of the valve. An adjustment screw 38 and lock nut 39 areprovided for varying the compression of the spring 40 in adjusting thevalve to cause the plunger to be unseated at the desired pressure. Theoutlet of the control valve provides two passageways 41, 42, thepassageway 41 extending to the forward end of the plunger, and thepassageway 42 extending 'to the rear end of the plunger and to theatmosphere through a slot 43 in the wall of the casing.

The forward end of the plunger is of much greater area than the outlet41, thereby causing the plunger to act rapidly and to seat against aseat 44 formed within the casing Afor preventing exhaust through theslot. The

ball 37 is slidably mounted and the air passes around the same throughgrooves in'the wall of the valve bore. After the control valve has beenactuated and the plunger is seated against the rear seat 44, the airflows through the unloader valve and thence to the throttle valve 27through cond uit 25a.

The area of the plunger 36 is greater than that of the inlet opening 36athereby causing quick action of the plunger when the ball 37 is unseatedand preventing fluttering of the plunger 36 since a greater pressure isneeded to close the valve than to open it. This insures the valvestaying open a` proper time even though the pressure drops due tovelocity head in the line. v

The trigger valve comprises a casing 45 and the casing and engaging abutton 48 formed on the exteriorly extending end of the plunger. Thelunger is formed with a-piston portion 49 of) a large diameter moving ina cylinder 50 within the casing, the conduit from the control valveentering into the cylinder at the forward side of the piston portion toforce the plunger outwardly. An exhaust port 51 is provided forexhausting the opposite side of the cylinder.

The plunger is formed to control the flow of air from the main air lineto the control piston. This is accomplished by having the main air line28 enter the plunger bore at one side, and the discharge conduit 29leading to the control piston entering the opposite side but slightlyoffset, and a groove portion 52 formed on the piston for overlapping therespective ports of the conduits into the plunger bore,

Therefore, when the trigger of the trigger valve is depressed to movethe piston toward the intake end of the cylinder, the groove portionthereof is disposed as above stated, this being the position forinitially starting the power stroke of the riveter.

When the pressure in the riveter has reached the desired degree and theunloading takes place, the plunger is moved outwardly and the grooveportion of the plunger disaligned from the two openings, thereby cuttingoff the air from the main air line and thereupon opening the line 29 toa second groove 53 in the trigger valve plunger, which groove isconnected to the atmosphere through a radially and axially formed port54 extending to the end of the plunger, and thence exhausting through aport 55 leading from the end of the plunger bore.

The air conduit 29 leading to the control piston connects to thecylinder 30xl thereof bei low the piston, and the sprin 31 is providedunder compression between t e opposite side of the piston and the endwall of the cylinder, the end wall of the cylinder being ported as i at56 to properly exhaust thatv side. A piston rod 57 extends from thecontrol piston through packing 58 tothe exterior and is connected to anarm 59, the arm in turn being connected to Ithe control lever link 21,which link is disposed parallel to the piston rod.

In order to make the two types of operation of the present deviceperfectly apparent, the following description of the operation is given.Assuming that the operator desires to apply a certain degree of pressureuniformly to the rivets, he then uses the tri ger valve 27. The normalposition of rest o the ias plunger in the bore or by any other suitablemeans.

Upon depression of the trigger 47, the air under pressure flows from themain supply line 28 through the trigger valve via the overlapping grooveand through the line 29 to the lower end of the control cylinder 30, Theline pressure being high quickly raises the control piston 30, andconsequently the link 21a is actuated to move the main valve 16 on theair motor to a position for supplying air from the main air line 17 tothe back of the main air piston 14. The toggle 9 is thereupon actuatedand the riveting stroke performed.

When the' degree of pressure to which the control valve has been set isreached at the back of the air motor, the air unloads through thecontrol valve 26 to the cylinder 50 in the trigger valve, actuating theplun er 4.6 to move the exhaust groove 53 in the p unger into registrywith the port of the line 29 leading to the control cylinder 30 and thelower end ofthe control cylinder 3()a is there- 'upon exhausted to theatmosphere. The spring 31 then acts to return the main valve 16 on theair motor to the position shown in Figure 1, in which position the airis supplied to the reverse side of the piston for reverse movementthereof, and the rear side is exhausted. The pressure in the controlvalve 26 then drops and the control valve again closes, permitting theair behind the piston 49 of the plunger 46 in the trigger valve 27 to beexhausted through the control valve, via the slot 43. If the operatorshould depress the trigger of the trigger valve unnecessary long, thepiston 49 thereof is of sufficient area that it will be moved by theunloading air pressure despite ordinary hand pressure on the trigger.

The foregoing movements have also moved the manually operated lever, butthis is immaterial inasmuch as the movement of this control lever is notof consequence in the described operation.

If no regard need be given to the pressure applied to the rivets, or ifit is desired to vary the pressures applied to each rivet, and accuracyof pressure applied is not essential, the

' hand lever is used entirely. It will be readily apparent that this ispossible inasmuch as the only active part when the lever is movedmanually, outside of the lever 21, the link 21",

and the valve 16, provided, of course, the

valve 32 in the line leading to the unloader valve is closed, is thepiston 30 in the control cylinder 30". This piston must be 'moved upagainst spring pressure and upon release of the hand lever, the springwill cause the return of the vpiston and lever 21 and thereafter suddenreversing of the power. The operator may either leave the hand lever onuntil the full line pressure is exerted, or he may release the samewhenhe feels that the proper pressure has been applied.

It is also possible to operate the trigger valve entirely manually withthe valve 32 closed for preventing automatic air supply to the triggervalve. The trigger could then be dispensed with and the head of theplunger grasped for manipulation of the valve plunger in bothdirections.

Having described my invention, I'claim 1. control system for an airdriven transmission, comprising in combination, a main cylinder, apiston therein in connection with the parts to be driven, a valve forlcontrolling forward and reverse movements of the main air cylinder, amain air line extending to said valve, a control cylinder, a pistontherein, a mechanical connection between the control piston and themainvalve, a trigger valve for connecting the main air line with the controlcylinder, a control valve in communication with the driving side of themain air cylinder and with the trigger valve, and a piston in saidtrigger valve actuated for a reversing of the control piston and mainvalve as the control valve acts at a predetermined pressure inthedriving side of the cylinder.

2. A control system for an air driven transmission, comprising, a mainair cylinder, a piston therein in connection with the parts to bedriven, a main valve for controlling said piston, a main air supply lineextending to said valve, a control cylinder and piston, mechanicalconnection between the piston and the valve, a hand lever attached tosaid mechanical connection, a trigger valve-for connecting the main airline to the control cylinder, a piston formed on said trigger valve, thetrigger valve casing having a cylinder therein containing the piston ofsaid trigger valve, and a control valve incommunication with the drivingside of the main air cylinder and with the reverse side of the cylinderin the trigger valve, whereby the trigger valve is actuated for areversing of v the control piston and main valve as the control valveacts under a predetermined pressure in the driving side of the powercylinder.

3. A control system for an air driven transmission,l comprising, a mainair cylinder, a piston therein in connection with the parts to-bedriven, a main control valve for said piston, a main air line extendingto said valve, a trigger valve, the main air line connected to said maincontrol valve, operative means between said trigger valve and said maincontrol valve, a piston formed on said trigger valve, the trigger valvecasing having a cylmder therein containing said trigger valve piston,and a control valve in connection with the driving'side of the main aircylinder and with the reverse side of the cylinder in the trigger valve,whereby the trigger valve is moved for actuating said main valve throughsaid means and reversing said main driving piston as the control valveacts under a predetermined pressure in the driving side of the powercylinder.

4. A control device for pneumatically operated mechanism, comprising, adriving cylinder, a driving piston therein, a main air supply lineconnectedto said cylinder, a main valve controlling the air to thecylinder, a trigger valve, said air supply connected to said triggervalve, said trigger valve including an air operative means, an airconnection between said air operative means of said trigger valveand thedriving end of said driving cylinder, valve means in said latterconnection permitting air flow fromy the driving cylinder to said airoperative means of said trigger valve at a predetermined drivingpressure in the driving cylinder, and means operative when there is airow from the driving cylinder to said air operated means of said triggervalve, said means extending from saidftrigger valve to the main valveand operative thereupon to reverse the main valve.

In witness whereof, I hereunto subscribe my name.

RAYMOND S. OSBORNE.

